1. Field of the Invention
This invention relates to a decorative lamp, and particularly to a decorative lamp set with a water-draining passage structure.
2. Description of the Prior Art
In the conventional decorative lamp string for Christmas season, the lamp sets are connected in series one another by means of two or more than two power-supply wires; every socket of a lamp set has a guide groove for receiving two copper terminals on two power-supply wires to plug into two copper-terminal grooves in a rectangular groove. The open end of the socket has a hollow cylinder for receiving a bulb base mounted with a bulb. Two copper wires of the bulb will be laid through a bulb hole of the bulb base, and then the tail ends of the two copper wires are bent to attach on two wall surfaces on both sides thereof respectively. After the bulb base is plugged in the socket, the two copper wires of the bulb will be in contact with the two copper terminals respectively; a plurality of lamp sets will be connected in series by means of power-supply wires to form into a lamp string.
The aforesaid lamp string can be hanged on a tree or other suitable place; the lamp string will swing with the wind. The plugging end of the power-supply wires of every lamp set is an open end. The open guide groove between the two power-supply wires is subject to having rainwater entered along the two power-supply wires and through the guide groove end of the socket. If the socket is in a still condition, the rain water would not flow into the guide groove because of the surface tension effect of water drops. In case of the socket being swung with the wind, the water drops on the guide-groove end would flow into the inner wall surface of the guide groove; if such water drops are not drained away, they would flow into a space between the two copper terminals on the power-supply wires to cause an electric shock to a person who touches the socket; therefore; a water-proof test has been listed in the UL standards, i.e., the UL organization will have a wet lamp set to swing with the wind, and will test whether such a lamp string can pass a water-draining test or not.
In a conventional decorative lamp string, please reference U.S. Pat. No. 5,605,395, both sides of the lamp base are furnished with two longitudinal separation channels respectively; after the lamp base is plugged into the hollow cylinder and the rectangular groove of the socket, the inner surface of the longitudinal separation channels on the hollow cylinder will locate above the wall surface of the bulb, while the outer surface thereof will be in contact with the wall surface of the hollow cylinder of the lamp base. The wider wall surface of the rectangular groove of the socket is furnished with a longitudinal groove, which is connected with the aforesaid longitudinal separation channel to form into a through longitudinal passage in the socket. Whenever rain water enter the guide groove for plugging power-supply wires, the rain water can be drained away through the longitudinal passage in the socket and along the inner surface of the guide groove of the socket. In fact, the longitudinal grooves of the aforesaid patent are furnished on the wide surfaces on both sides of the rectangular groove for plugging the two copper terminals of the two power-supply wires; the guide groove between the two power-supply wires is not isolated; when rain water enters the guide groove along the power-supply wires, the rain water will stay and accumulate between the two copper terminals. As a result of the surface tension effect of water drops, the water drops will be unable to drain away upon the lamp set swinging with the wind because of the passage being two narrow; consequently, electric shock might take place.
According to skill as disclosed in the aforesaid patent, symmetrical longitudinal separation channels furnished on the cylinder surface of the lamp base have long been disclosed in U.S. Pat. No. 5,443,399; the cylinder surface of the bulb base of the aforesaid patent is furnished with symmetrical longitudinal separation channels. After the bulb base is mounted with a bulb, and the bulb base is plugged into the hollow cylinder and the rectangular groove, the separated cylinder will clamp the bulb in place without rotation; otherwise the two copper wires pulled out will be twisted to cause a short-circuit.